Association between chemokine receptor 3T51C gene polymorphism and different clinical asthma phenotypes in Egyptian asthmatic children

Abstract

Background Asthma is a heterogeneous disorder, which is affected by interaction between genes and the surrounding environment. Chemokine receptor 3 (CCR3) which is expressed over eosinophils and Th2 lymphocytes has a significant role in chemoattraction of those cells to inflammatory sites which symbolizes a key mechanism in asthma. Aim A trial to detect the association between CCR3 T51C gene polymorphism and different asthma phenotypes (allergic march phenotype, cough-predominant asthma phenotype, and wheeze-predominant asthma phenotype). Patients and methods A case–control study was conducted comprising 60 asthmatic patients and 100 healthy controls. Asthmatic children were divided into three groups of 20 patients each, group 1 allergic march phenotype (wheeze asthma phenotype with allergic rhinitis and/or atopic dermatitis), group 2 cough-predominant asthma phenotype, and group 3 wheeze-predominant asthma phenotype. The included cases and controls underwent total serum immunoglobulin E (IgE) using the enzyme-linked immunosorbent assay technique, peripheral eosinophilic percent, and PCR-restriction fragment length polymorphism for CCR3 T51C gene polymorphism. Results Asthmatic children showed significant increase in crowding index, family history of bronchial asthma, parental smoking, parental consanguinity, and total serum IgE than controls. Also, the CCR3 T51C gene polymorphism was found in Egyptian asthmatic children but no significant association concerning this polymorphism and different clinical asthma phenotypes was detected. Conclusion In conclusion, allergic march phenotype showed significant higher frequency with positive family history of asthma when compared with cough and wheezy asthma phenotypes. Also, parental consanguinity showed higher frequency in cough phenotype compared with allergic march phenotype. Furthermore, the CCR3 T51C gene polymorphism is found to be present in Egyptian asthmatic children, but there is no significant association between CCR3 T51C gene polymorphism and different asthma phenotypes. So, larger scale studies are needed. However, the TT genotype showed higher frequency in the studied phenotypes compared with CC and CT genotypes while asthmatic cases with the CC genotype showed higher total serum IgE compared with those with TT and CT genotypes.